Bracket placement on the lingual surfaces of a patient's teeth for "straight wire" orthondontics is much more difficult than on the buccal surfaces of the teeth because it is the buccal surfaces of the teeth that are to be aligned to form an anatomically correct dental arch. While there are variations in buccal anatomy, the attachment of the brackets directly to the surfaces to be aligned negates most of the variations and produces excellent results with minimal archwire bending. Ease of manipulation to achieve quality finished orthondontic case is directly related to the quality and precision of bracket placement.
Conversely, the lingual surfaces of a patient's teeth are not the surfaces to be aligned. The lingual surfaces do not have a constant relationship with the buccal surfaces, therefore a constant appliance configuration for each tooth as in straight wire mechanics will not achieve consistent quality results from minimal archwire manipulation.
The indirect bonding technique for installation of orthodontic brackets requires two basic elements for success. First, an accurate measuring or placement device for the determination of the position of an archwire slot (includes tip, torque, rotation and height, and in/out) on the buccal surface of each tooth which will position that surface ideally if the archwire slot were engaged with a full sized pre-formed archwire. This accurate measuring or placement device would be applicable to the straight wire concept of orthodontic therapy. Secondly, a jig or transfer device which would transfer the buccal archwire slot position to a parallel lingual slot position (includes tip, torque, rotation, in/out and height) which could be attached to the lingual surface of the patient's teeth, i.e., the archwire slot on the lingual surface of the patient's teeth would be directly related to the buccal surface rather than to the lingual surface. It makes no difference whether the lingual archwire slot opens to the occlusal or to the lingual. Because of the accurate measurement of the buccal surfaces, the same bracket installation apparatus could be employed for very accurate buccal indirect bonding as well as lingual bonding. Variations in "prescriptions" used by different orthodontists could be accommodated simply by changing the torque and/or the angulation of the archwire slot. Variations in over corrections can also be accommodated for rotation, torque, angulation, etc.
Basically, it is desirable therefore to provide apparatus for installation of orthodontic brackets to the labial and facial surfaces of a patient's teeth or on the lingual surfaces of the patient's teeth with the positions of the archwire slots of the brackets being oriented in each case in relation to optimum archwire slot positioning on the buccal surfaces of the teeth.